In the stunned silence which followed London’s move, Australia found itself in an unexpected position to take action, even though it was half a world away.

Nobody would have believed it would be an Aussie initiating hostilities on behalf of the Empire.

Nor would they have expected Australia to be the source of such a significant intelligence breakthrough — and so soon.

The actions of Fort Nepean’s gunners, the initiative of Captain John Tracey Richardson and the analytical mind of Mr William Wheatley remain largely unheralded. Now you can read them.

SECRET STORIES OF A FEW BRAVE MEN

Opening salvo ... one of Fort Nepean’s six-inch guns, pictured with its crew in 1914.Source:Supplied

At the moment the war started, the German-flagged steamer SS Pfalz was in Melbourne. Its captain was well aware of the impending crisis, and what it would mean to be in a British Empire harbour once the first shots were fired.

Little would he know they would be directed at him.

Captain Kuhlken had put his crew on immediate notice to leave. All he had to do was pass the Port of Melbourne’s Heads.

First target ... a shot was fired “over the bow” of the SS Pfalz.Source:Supplied

On board the SS Pfalz was 200 tonnes of coal. He knew this precious fuel would be redirected to supply the Pacific Squadron of the Imperial German Navy.

So too did the Australian navy.

In anticipation of the expiration of the diplomatic deadlines that marked the final days of peace, Victorian naval officers had manned an “examination centre” at the entrance to Port Philip Heads. Fort Nepean.

Captain Kuhlken set sail on the morning of August 5, 1914. He thought he had several hours to spare.

The soldiers and sailors stationed at Fort Nepean in Port Melbourne received their orders just as the German ship approached a line of fire which threatened to expose the suburb of Queenscliff to any stray shells.

With moments to spare, at 12.39pm, the gunners opened fire.

The six-inch gun hurled its 45kg shell at the steamer. A geyser of water went right over the ship.

A pilot boat rushed alongside: Pull up, or the next shot will be aimed right at you, came the shouted warning.

Captain Kuhlken knew he was defeated.

His ship — heavily laden, unarmed and unarmoured — stood no chance against the heavy guns of the fort.

By 5.15pm the SS Pfalz was tied up at the pier again and her crew detained.

She was the first German “loss” of the war.

And Fort Nepean had fired the first shot on behalf of the British Commonwealth.

Learning enemy secrets ... William Wheatley used the captured codebooks to decipher German signals — and had a win on Melbourne Cup Day.Source:Supplied

Risk and reward ... Captain John Tracy Richardson bloodlessly captured a German ship and its vital codebook through his own initiative.Source:Supplied

AMBUSH IN THE DARK AND A CAPTURED CODEBOOK

Even as the SS Pfaltz settled back into the Melbourne docks, attention shifted to the scattering of other German vessels in Australian waters.

One ship, the SS Seydlitz, left Sydney on August 4, 1914 without receiving its Australian clearance papers, triggering suspicions that it would warn other German ships in the region about Australia’s involvement in the war.

The Royal Australian Navy’s attention turned to another German merchant ship, the unfortuantely named SS Hobart, which was still in Australian waters, on its way from Fremantle to Melbourne.

The priority was to ensure German ships were not able to communicate to each other, so the RAN hatched a plan to jam any potential telegraph exchanges by keeping up incessant telegraph traffic. The second part of the plan was to maintain the impression of Australian neutrality, and war-like defences were removed from the coast.

Late in the afternoon on August 11, the Hobart arrived off Victoria’s Port Phillip Heads.

Ship’s captain was wary: He knew tensions were high. But he had not heard any news — or received any signals — revealing the declaration of war.

He decided to stop his ship hoping to assess the situation before passing inside.

A boat approached, full of smartly dressed civilians. Perhaps they could offer some news?

AUSTRALIAN BOARDING PARTY SENT IN DISGUISE

Instead it was full of Australian naval officers. They were a boarding party sent to seize the ship.

In bowler hat and overcoat, his pistol in his pocket, the raiders’ commander — Captain John Tracy Richardson — only revealed his true identity when he faced the SS Hobart’s captain.

Taking off his overcoat to expose his naval uniform beneath, Captain Richardson formally took the ship and its crew as prisoners of war.

But Captain Richardson wanted more.

So he let the German skipper roam the ship. Captain Richardson hoped the man would attempt to recover — and destroy — any secret documents.

Hiding in the captain’s cabin, Captain Richardson waited. Sure enough, in the early hours of the morning, two men crept into the darkened room and opened a secret compartment.

Captain Richardson, flicking on his torch and raising his gun, quickly took them in hand.

One of the documents proved particularly vital: A secret codebook known as HBV which allowed German merchant ships to communicate with German warships.

Now it just needed to be understood.

Key to victory ... the Royal Navy’s success at the Falkland Islands in December 1914 was in part due to Australia’s code-breaking efforts. Here HMS Inflexible rescues sailors from a sunken German warship.Source:Supplied

CRACKING THE CODE AND A VICTORY AT SEA

The book was the only copy in British hands and so all German codes the Admiralty intercepted were sent to Melbourne to be decoded.

Cracking the code fell to Frederick William Wheatley, a former Royal Australian Naval College instructor and a fluent German speaker.

It was a complicated code, involving 450,000 possible four letter groups. Its use was often confined to routine announcements between vessels, although the allies did not know that.

In the chaotic opening weeks of the war, the value of such intelligence was hard to gauge. But Wheatley believed any advantage over the enemy was priceless.

He became consumed by the task, working on the puzzle for three days and two nights, filling “thousands’’ of foolscap sheets of paper with letters, checking and cross-referencing.

On Melbourne Cup Day 1914, an exhausted and dispirited Wheatley decided to step away from his desk to go to Flemington to watch the race.

Maybe it was the inspiration he needed — back at his desk by 6pm, Wheatley had cracked the code.

“These messages…were all from the German Pacific squadron and gave their itinerary through the Magellan Straits, up to the Abrolhos Island off Brazil, …and then to West Africa,’’ Wheatley wrote.

Copies of the decoded books were sent to the Admiralty, and there is a view that the decoded messages enabled the British fleet to race to the south Atlantic where it defeated the German Pacific Squadron at the battle of the Falkland Island on December 8.

Although the war would drag on for four more years, Australia’s role was already cemented.